The Blues trailed 1-0 in Cumbria before the attacking duo were introduced to the action just past the hour mark to devastating effect.

Ben Tollitt, left, celebrates with Caolan Lavery. Picture: Joe Pepler

Winger Tollitt’s impact was felt within two minutes of his arrival, as the pacy youngster beat his man down the right before crossing for alert Pompey striker Caolan Lavery to convert from close range.

Two minutes later, McNulty got in on the act, pouncing on a defensive mistake to drive into the box and slam a fierce left-footed shot beyond Carlisle goalkeeper Mark Gillespie.

It was the Sheffield United loanee’s first goal for the Blues following his arrival earlier this month and no less than the visitors deserved having dominated the game throughout.

But there was to be a late and cruel twist for Cook’s side as home skipper Danny Grainger struck a stunning 30-yard effort in the last of five minutes added time – his second goal of the game.

People can see what Tollitt brings to the team straight away – he is forcing his way into the reckoning by the minute.

Pompey manager Paul Cook

Regardless, Cook was boosted by Tollitt and McNulty’s impressive impact on proceedings.

He said: ‘It was great for Ben (to perform well) in front of our travelling support because it gave them a lift going home.

‘People can see what Tollitt brings to the team straight away – he is forcing his way into the reckoning by the minute.

‘He is brave in what he does and he has the energy to hurt people.

‘Great credit to him, he has got a lot to learn as a young player.

‘If he keeps his feet on the ground I am sure he will have a good career.

‘Marc McNulty is a good player.

‘He scores goals – our fans won’t be disappointed with McNulty.

‘He is going to get more and more game time as we go on.’

Cook refused to take credit for an inspired double change but explained the thinking behind the switch in personnel.

He said: ‘I made good subs but I just do my best to win games for people.

‘In football – even for supporters like ourselves – people can’t handle disappointment.

‘We weren’t handling it too well.

‘We started giving the ball away very cheaply and there were turnovers of possession so I felt a little bit of freshness would do the team a world of good – and it did.

‘We have got effective players now – we have got players who want to go forward.

‘We are trying our best to keep everyone happy with what we are doing and at the same time changing the whole profile of the squad to make us more energetic and more of a threat going forward while being defensively sound.’

Aside from Carlisle’s last-gasp strike to prevent the Blues from claiming an overdue League Two win, the other major blow for the visitors arrived in the form of a head injury to McNulty.

Cook, though, was hopeful the front man – forced off the pitch 10 minutes after his arrival – would be available for tomorrow night’s clash with York (7.45pm).

He said: ‘It was the physio who brought him off – Marc wanted to stay on the pitch.

‘I am sure he will be alright for tomorrow night and it is a game we are looking forward to.’